Unit 9 · 4 lessons
The Twentieth Century and Popular Music
Tensions and altered chords, modal harmony, symmetric scales, tritone substitution and chord–scale thinking.
Goal of this unit
Connect popular-music notation and function back to classical theory.
Prerequisites
Lessons
- 1
Extensions and Altered Tensions
about 16 minKeep stacking thirds above the seventh and you get 9ths, 11ths, and 13ths. This lesson covers what decides which extensions are usable, and why altered tones are free only above a dominant seventh.
Tools used in this lesson: Chord Finder
- 2
Modal Harmony
about 15 minAbandoning harmony driven by tension and resolution in favor of music sustained by the color of a single mode. This lesson covers how characteristic tones are used, and why dominant-to-tonic motion is avoided.
Tools used in this lesson: Mode Dictionary
- 3
Whole-Tone and Octatonic Scales
about 15 minScales built by repeating one interval return to the same collection of notes when transposed. Having no fixed tonic is exactly why twentieth-century composers used them as color.
Tools used in this lesson: Scale Dictionary
- 4
Tritone Substitution
about 15 minMove the root of a dominant seventh by a tritone and the core of its tension survives. This lesson covers how the third and seventh exchange roles, and the half-step bass descent that results.
Tools used in this lesson: Chord Progression Analyzer